Almost all residential wiring was initially made of copper due to its overall performance as a conductor associated with a feasible cost point. That said, aluminum has also been used for residential construction. Aluminum provides a better conductivity to weight ratio compared to copper which makes it a more attractive choice for power wiring in applications where weight is important (e.g. airplanes). Still, copper generally won the aluminum v. copper debate when all issues were considered. However, during the Vietnam War era (1960s through 1970s) the price of copper wiring reached at least triple the price of aluminum wiring tipping the aluminum v. copper choice in the favor of aluminum. Thus, the use of aluminum wiring became popular during such time.
Unfortunately, shortly after aluminum wiring became popular for use in residential homes, some problems started to appear. Such problems included flickering lights, warm cover plates on switches and receptacles, and burned insulation on wiring. Restated, there was an overheating issue which could lead to a fire. The problem was at the connections between the wiring system and the end-point (i.e. a light, receptacle, appliance etc.) where copper was still in use.
For electricity, resistance to current flow causes the generation of heat. Such is generally unwanted but cannot be avoided (only minimized). Notably, the best flow path is a continuous flow path with no interruptions as all interruptions have a higher resistance to current flow compared to a continuous wire. Thus, the ideal electrical path from a power source to a power user is a continuous wire. Obviously, a continuous flow path is not possible at the end-points (e.g. receptacles, switches, light fixtures, appliance connections, and at the power/breaker panel) where the power is made available. The best that can be done is to make the connections as low resistance as possible. Thus, the best connection is a “tight” connection where the wiring is clamped or soldered to (or both) the connection point (end-point).
For the residential wiring system, receptacles, switches, light fixtures, appliance connections, and power/breaker panel “connections” were designed for copper wiring. When aluminum wiring started being used as the wire that connected the breaker panel to a light fixture (for example—or some other end-point), such meant that aluminum wiring was being connected to end-points comprising copper and designed for connecting to copper wiring. A first problem with connecting aluminum wiring to a copper end-point is the use of dissimilar metals at the connections. The problem of connecting two different metals is that different metals have different rates of expansion. As the current in an electrical circuit (and thus, the connection) increases the temperature of the aluminum and copper increased but at different rates. Such had a tendency to make the connection loose over time. A loose connection is a higher resistance connection which caused even more heat generation at the connection which caused more expansion until the connection failed.
A second problem with using dissimilar metals relates to the chemical reaction between the two metals. When aluminum is connected to copper a chemical reaction called “oxidation” occurs. Oxidation causes a high-resistant connection, and as noted above, higher resistance means more heat which causes more oxidation which causes more heat, and so on, until the connection fails.
One solution to the aluminum/copper problems includes special connectors and wiring procedures. While modern technology makes it possible for the do-it-yourself electricians to work with aluminum wiring a necessary first step in such a process is to make the do-it-yourselfer (as well as professional electricians) aware of the issue. A second step is to educate the repair person about the proper process for connecting two different types of electrical wires. Finally, the repair person needs to acquire the proper products for connecting two different types of wire.
Embodiments of the current invention address at least the issues identified above.